But if most Americans are so convinced of the value of college, why are we having the argument?

One reason may be how the public is processing two conflicting worries: their conviction that college is necessary is rising, even as they're increasingly worried that a diploma is out of reach financially.

In our Squeeze Play studies, we've found the number of people who think that a higher education is "absolutely necessary" for success has jumped dramatically, up from 31 percent as recently as 2000 to 55 percent in our last two studies, in 2008 and 2009. Yet nearly seven in 10 also say there are many qualified people who don't have access to higher education, up from 47 percent in 2000.

Six in ten Americans agree that "colleges could take a lot more students without lowering quality or raising prices." Over half (54 percent) say that "colleges could spend less and still maintain a high quality of education."

It's these kind of doubts that the critics of colleges may be tapping into: not so much that there isn't value in college, but that colleges may not be doing everything possible to keep their prices in line. You can believe something is absolutely necessary, and still wonder whether you paid too much for it.